How to implement a single instance Java application?

Question

Sometime I see many application such as msn, windows media player etc that are single instance applications (when user executes while application is running a new applicatio

Answer 1

If the app. has a GUI, launch it with JWS and use the SingleInstanceService.

Update

The Java Plug-In (required for both applets and JWS apps) was deprecated by Oracle and removed from the JDK. Browser manufacturers had already removed it from their browsers.

So this answer is defunct. Only leaving it here to warn people looking at old documentation.